(6R,10R)-6,10,14-Trimethylpentadecan-2-one is an important intermediate, particularly for the synthesis of (R,R)-isophytol[=(3RS,7R,11R)-3,7,11,15-tetramethylhexadec-1-en-3-ol], (R,R)-phytol and tocopherols.
Isophytol, phytol and tocopherols are chiral substances, the latter two of which occur in nature in the form of the “all-R” stereoisomer. Phytol contains 2 stereocentres and in addition a trisubstituted carbon-carbon double bond which gives rise to E/Z-steroisomers, while isophytol and tocopherols have 3 stereocentres. Therefore, there are multiple isomers.
It has been shown that of the naturally occurring stereoisomers of tocopherols, (2R,4′R,8′R)-tocopherols, particularly (2R,4′R,8′R)-α-tocopherol, have the highest bioactivity (biopotency).
As natural sources of (2R,4′R,8′R)-tocopherols and (R,R)-phytol, however, are very limited, the market has a strong need for an effective synthesis of (2R,4′R,8′R)-tocopherols and (R,R)-isophytol and (6R,10R)-6,10,14-trimethylpentadecan-2-one, the starting material of these products, which is useful for industrial scale application.
As, furthermore, higher bioactivity (biopotency) has been shown, for example by H. Weiser et al. in J. Nutr. 1996, 126(10), 2539-49, to occur in general by tocopherols having the R-configuration at the chiral centre situated next to the ether oxygen atom in the ring of the molecule (i.e. 2R-configuration), as compared to the corresponding isomers having S-configuration, there is a strong need for an effective and industrial scale synthesis of (2R,4′R,8′R)-tocopherols, particularly (2R,4′R,8′R)-alpha-tocopherol.